Allow Panache bytecode enhancers to benefit from class transformers caches

[Sanne]

See also: https://quarkusio.zulipchat.com/#narrow/stream/187038-dev/topic/Bytecode.20transformers.20caches.20for.20Hibernate.20entities

[Sanne]

"Undrafted" and rebased, let's have CI opinions as well.

I described the rationale above and think it should be safe after having convinced myself while writing the rationale :) but let's have @FroMage review it please.

[Sanne]

Updated & rebased:

• Reverted the second change; so we'll cache the transformation of entities which seems safe and also gives us the strongest benefits as it will allow to skip the other enhancements from Hibernate ORM as well, which are heavy.
• Added a note linking to the above caveats in the code for the second transformation suggesting what one could do eventually, if we need to come back to this.

[quarkus-bot]

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It should be safe to merge provided you have a look at the other checks in the summary.

You can consult the Develocity build scans.

Amended the PR to not cache the client-side transformations

[FroMage]

Yeah, that seems safer, I suppose transforming the accessors is only local-class dependent.

[Sanne]

Pushed a follow-up as #40629